java - 无法打开在 firebase 上上传的 pdf 文件

Question

我已将 pdf 文件上传到 firebase，也能够在 ListView 中检索它，但是当我单击 ListView 文件时，它不会打开

我已将 pdf 文件上传到 firebase，也能够在 ListView 中检索它，但是当我单击 ListView 文件时，它不会打开

我已将 pdf 文件上传到 firebase，也能够在 ListView 中检索它，但是当我单击 ListView 文件时，它不会打开

package com.example.studentcoordinator;

import android.content.Intent;
import android.graphics.Color;
import android.net.Uri;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;
import java.util.List;

public class Viewuploadedfiles extends AppCompatActivity {

    ListView viewuploadedfiles;
    DatabaseReference databaseReference;
    List<uploadPdf> uploadPdfs;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_viewuploadedfiles);

        viewuploadedfiles = findViewById(R.id.listuploadedfiles);
        uploadPdfs = new ArrayList<>();

        viewAllFiles();

        viewuploadedfiles.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                uploadPdf uploadPdf = uploadPdfs.get(position);

                Intent intent = new Intent();
                intent.setType(Intent.CATEGORY_OPENABLE);
                intent.setData(Uri.parse(uploadPdf.getUrl()));
                startActivity(intent);
            }
        });


    }

    private void viewAllFiles() {

        databaseReference = FirebaseDatabase.getInstance().getReference("uploads");
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {

                    uploadPdf uploadPdf = postSnapshot.getValue(com.example.studentcoordinator.uploadPdf.class);
                    uploadPdfs.add(uploadPdf);

                }

                String[] uploads = new String[uploadPdfs.size()];

                for (int i = 0; i < uploads.length; i++) {

                    uploads[i] = uploadPdfs.get(i).getName();

                }

                ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, uploads) {

                    @Override
                    public View getView(int position, View convertView, ViewGroup parent) {

                        View view = super.getView(position, convertView, parent);

                        TextView myText = view.findViewById(android.R.id.text1);
                        myText.setTextColor(Color.BLACK);

                        return view;
                    }
                };
                viewuploadedfiles.setAdapter(adapter);
            }

            ;

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }
}

它应该打开 ListView 中列出的 PDF 文件，而不是在之前的 Activity 中重定向我

Answer 1

看来您的 Intent 并未指示 PDF 使用读取 PDF 文件的应用程序或读取 PDF 文件的网站打开。这就是为什么它只是返回到之前的 Activity 。

要在浏览器中打开 pdf，

Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(pdf_url));
startActivity(browserIntent);